The use of ozonated water as a sanitizer to extend the
shelf life of fresh-cut lettuce and the effect onthe antioxidant constituents (polyphenols and vitamin C) were investigated. Fresh-cut
iceberg lettuce(
Lactuca sativa L.) was washed at 4
C using three different ozonated water dips [10, 20, and 10activated by ultraviolet C (UV-C) light mg L
-1 min total ozone dose], and the dips were comparedwith water and chlorine rinses. Treated lettuce was packaged in air or active modified atmospherepackaging (MAP) (4 kPa of O
2 + 12 kPa of CO
2 balanced with N
2) and stored for 13 days at 4
C.Despite its strong oxidizing activity, ozonated water did not stimulate the respiratory activity of fresh-cut lettuce. Moreover, ozonated water maintained the initial visual appearance of fresh-cut lettuceand controlled browning during storage in air. Initially, ozonated water and chlorine reduced the totalmesophilic population by 1.6 and 2.1 log, respectively, when compared with water. Active MAP waseffective in controlling total microbial growth, achieving 2.0 log reduction in relation to samples storedin air at the end of storage. On the other hand, active MAP caused a 2.0-3.5 reduction of coliformson sanitized samples compared with water-washed samples. The most efficient treatments wereozone 20 and ozone 10 activated by UV-C, which were as effective as chlorine. Changes in individualphenolic compounds were independent of the washing treatments. In air, chlorogenic and isochlorogenic acid contents increased not
iceably after 13 days while monocaffeoyltartaric and dicaffeoyltartaric acids remained unchanged. MAP effectively suppressed accumulation of caffeoylquinicderivatives, whereas caffeoyltartaric derivatives decreased during MAP storage to reach similar levels.The content of vitamin C (ascorbic acid and dehydroascorbic acid) decreased during storage,particularly under MAP. Ozonated water could be an alternative sanitizer to chlorine for fresh-cutlettuce due to good retention of sensorial quality and browning control with no detrimental reductionin the antioxidant constituents.Keywords: Lactuca sativa L.; browning; chlorine; microbial quality; minimal processing; modifiedatmosphere packaging; polyphenols; sanitizers; sensory quality; vitamin C